Rocker Arm help
Rocker Arm help I had a small tapping noise coming from the passenger side valve cover. You couldn't hear the tapping at idle, but while driving around 1200-1300rpm, you could hear the tapping and also the car had a hard time idling. I just installed LS7 lifters back in June '08. So I proceed to pull the valve covers and afterwards, I grab a flathead screwdriver and began to tap the rocker arms from the side. All were tight except one. It moved side to side and up and down freely. I even grabbed it with my hand and raised the rocker up and down. (it was just flapping). So then I grabbed an 8mm socket and tried to tighten it, but it was already tight. So I took the rocker arm off. I turned the motor over about an 1/8 way and put the rocker on the pedestal and bolted it down and the rocker didn't move freely anymore, it was tight. I left it like that then went inside to finish watching the Giants runs over the Browns, but fell asleep afterwards. I drove my alt. vehicle to work this morning and I was just thinking while here at work. My question is once the motor makes another 1/8th turn or a full turn, will that rocker arm have the same play in it as it did before at the same position it was loose? Or should I tighten it, then rotate then motor and see if it tightens some more?
It should be tight on the base circle. It was not. When you rotated it, the cam lobe pushed the lifter & push rod up & made the loose rocker tight. Rotate the motor until the valve is closed (tallest spring dimension) & tighten. Be careful not to tighten too much because the lifter has bled down & is lower than its' operating position. So, I would tighten & then back off 1/4 turn; or you can turn the engine over with the starter (injectors disconnected) for say 30 rotations & build a little lifter pressure (20-25 psi); then jump out of the car, turn the engine 'till the valve is closed, & then tighten the nut. This should get you close. Once you can't wriggle the push rod, go another 1/4 to a 1/2 turn.
It should be tight on the base circle. It was not. When you rotated it, the cam lobe pushed the lifter & push rod up & made the loose rocker tight. Rotate the motor until the valve is closed (tallest spring dimension) & tighten. Be careful not to tighten too much because the lifter has bled down & is lower than its' operating position. So, I would tighten & then back off 1/4 turn; or you can turn the engine over with the starter (injectors disconnected) for say 30 rotations & build a little lifter pressure (20-25 psi); then jump out of the car, turn the engine 'till the valve is closed, & then tighten the nut. This should get you close. Once you can't wriggle the push rod, go another 1/4 to a 1/2 turn.
Do you know why the one stud on the rocker arm was already tight and I couldn't go any tighter and the rocker was moving moving freely before I even took it off? Does that mean the rocker arm was loose and I should have just turned the motor and tried to tightened? the push rod was not bent and there was no visible damage to the spring...
